Monday, July 14, 2008

Early this summer I published our list of goals for the summer and number nine was "build a soapbox racer" (otherwise known as a go cart). Well we can check that one off the list because last week we fulfilled our Nascar dreams by hosting the first ever Go Cart Grand Prix and fun was had by all.

So I've got pictures and instructions should you have the inclination to try it yourself. It was an easy project and the kids and I had lots of fun planning and building our sweet ride.

We called our creation "The Wind Scorpion" (which you might remember is another name for the camel spider). There were some issues about whether a "Ninja Wind Scorpion" were more fearsome than a mere "Wind Scorpion" but in the end we figured the simplicity and elegance of "The Wind Scorpion" would promote a general fear among our competition. The kids were even cocky enough to stick a sign on the back reading, "If you can read this you're losing."

Of course that was all a bit premature and our competition had a ringer in the pit crew. Apparently the other driver's grandfather is an Air Force mechanic who works on the F-15s so I guess if anyone knows anything about building machines for speed it would be him and we lost miserably. No worries, just wait until we build the next one, it's going to rule the pavement.

Here's what you'll need:

Some friends who have as much time on their hands as you do. Unless you want to race by yourself. Of course you may not want to invite friends who have much MORE time than you because ten-to-one they'll build a machine guaranteed to leave you in the dust.

1 1-inch by 10-inch main board five feet long. This will be the main board for the chassis.

2 cross pieces to support the axles. We used cross pieces that were 2-inches by 3-inches--one 3-feet long for the back axle and one 2-feet long for the front.

A Lazy Susan swivel for the front steering joint.

2 1/2-inch diameter, 3-foot long steel rods for the axles. Don't let the guy at Lowe's tell you that you need threaded rods, ignore him, you'll definitely need smooth rods for speed. Take it from us who learned the hard way.

4 wagon wheels to fit on the 1/2-inch rods, the ones with ball bearings in them are probably best and this will be the most expensive part of the project, running about $8 a piece.

2 small eye bolts for attaching the steering rope to the front cross piece plus two yards of steering rope.

4 1/2-inch cap nuts plus washers for securing the wheels on the axles.

Wood screws of various sizes to hold it all together--plan for plenty of them because they'll get dropped and lost along the way.

A trash can for the body--and some 1/4-inch stove bolts with washers to secure it to the chassis without tearing the plastic.

I also used white Contact paper for decals that the kids designed with permanent markers.

A 1-inch by 2-inch board for a pivot break fixed to the chassis with a 3-inch lag bolt.

And finally you'll need a street where you can race. Preferably one that's a dead end, paved, gently sloped and without pot holes. I'd give you the name of the street we used but I'm guessing the people who live there might not appreciate me turning their street into The Fast and the Furious.

Now here's how it goes all together:

1. Screw the Lazy Susan swivel to the front of the long board then screw the cross piece on top of that. Your front board should swivel and steer quite nicely now.

2. Screw the back cross piece onto the main board.

3. Using strips of plumber's tape and wood screws, secure the axles to the undersides of the cross pieces.

4. Put the wheels on with the washers and cap nuts--you might also want to get some lubricant in there while you're at it.

5. We used an extra board as a back rest though this is optional, ditto on the rubber dish rack mat we used as a seat. If you want these now's the time to screw them in place.

6. Attach the break to the side with a pivot joint. You might have to experiment with this because we all felt that after our race the side break wasn't as effective as foot pedal breaks would be. Not sure how they'd be designed but you might give this some thought and come up with your own ideas.

7. Screw the body (trash can) in place. Our friends even had a grill and headlights on their car. I had the boys put decals made from white Contact paper they'd decorated with permanent markers and self-adhesive reflectors on the back. Be creative--our friends went to an auto parts store and asked for automotive parts stickers and the store gave them out for free.

8. Attach the eye bolts to the front cross piece near where the feet will rest. String the rope through the eye bolts and tie it so you have a loop of rope to steer with--if it's nylon rope you can burn the ends to melt it and make it more secure. When riding, keep this rope taut.

And finally, if you'd like to see video of the race here's the clip I put together to capture the experience. It was wise to require the kids to wear helmets and pads because the steering rope had to be held taut or they'd flip. The cars had a hand break on the side but the kids found it more effective to drag their heels off the front cross piece where they rested their feet.

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Wow, kudos, Michelle! That's one awesome project. I want a summary of your kids' "what I did this summer" report at the beginning of school: We went hunting for gold, made a whip out of duct tape, painted the house black and freaked the neighbors out, built a go cart, made a pool table ...